Uludag Fir Wood Research Articles

Mechanical characterization and strain analysis applied to the heat treatment of wood materials, by means of digital image correlation

Digital image correlation (DIC) was used to examine the strain distribution of heat-treated beech and Uludag fir woods in mechanical testing. It also evaluated the effects of the heat treatment process on the properties of the wood samples. The physical (mass/density loss, dimensional stability, color change, and surface roughness), mechanical (flexure test and compressive strength), morphological, thermal, and structural properties of the heat-treated wood were examined. It was determined that the heat treatment parameters can be optimized using the DIC method. The test results showed that although heat treatment can provide improved physical and thermal properties, it caused micro-crack formations and collapses in the wood cells. As a consequence, the mechanical properties of the heat-treated wood materials decreased with the heat treatment process. There were slight differences in the curves of the samples according to Fourier infrared and X-ray diffraction analyses. Morphological characterization showed that the heat treatment triggered large cracks in the cell wall and lumens and the morphological structure of heat-treated wood was affected at large percentages.

Dimensional Stability of Uludag Fir Treated with Liquid Nitrogen after the Steam Test

In this study, the effect of liquid nitrogen on dimensional stability of Uludag fir (Abies bornmulleriana Mattf) wood after exposing to the steam test was determined. Test samples were treated with liquid nitrogen (LN) for 1, 4 and 10 hours. Subsequently both samples treated with liquid nitrogen and control samples were conditioned to 12 % MC. Dimensional stability of Uludag fir wood was measured after exposing to steam for 2, 6, 12, 24, 48, and 96 hours according to the procedure of TS EN 317. Consequently, different values of dimensional stability of specimens treated with liquid nitrogen were observed.

Prediction of Withdrawal Strength of Nail of Uludag Fir Wood by Using Artificial Neural Network (ANNs)

In this study, the effects of type of nails material and grain angle of wood on the withdrawal strength of nail have been researched. For this purpose specimens were firstly cut in different sections from Uludag Fir (Abies bornmulleriana M.) wood. The tests of static nail strength were carried out according to the standards of TS EN 13446. Secondly, an artificial neural network system was built by using data obtained in an experimental study for the prediction of withdrawal nail strength. The comparison between the experimental data and predicted data was also carried out.

The Effect of Liquid Nitrogen on Retention in Uludağ Fir Wood Treated with Boric Acid and Borax

In this study, the effect of liquid nitrogen on retention of Uludag Fir wood after exposure to boric acid and borax was determined. Before treating with liquid nitrogen, specimens were conditioned to 4 different moisture contents (oven dry, 12%, 28%, and green). Liquid nitrogen treated specimens for 1 hour, 4 hours and 10 hours. Then, all specimens were conditioned to 12% moisture content (MC). Test specimens were exposed to chemicals such as borax and boric acid for three times: short (2 min), normal (1 hour) and long (1 week). Dipping method was used for the impregnation process. For control, specimens were treated with borax and boric acid without treating with liquid nitrogen. Consequently, there is a linear relationship between moisture content and retention. Since moisture content increases the amount of retention increases as well.

Effects of heat treatment and surface roughness on bonding strength

The objective of this study was to determine the effect of heat treatment on bonding strength of the samples from four different species, namely Scotch pine, oriental beech, white oak and Uludag fir woods. The samples were exposed to three temperature levels of 120°C, 150°C and 180°C for time periods of 2 and 6h. Based on the findings in this work white oak samples had the highest average roughness (Ra) and maximum roughness (Rmax) values of 9.49μm and 48.9μm, respectively. It appears that heat treatment enhanced overall surface quality of the samples.

Investigating changes in the chemical consitutents and dimensional stability of heat-treated hornbeam and uludag fir wood

Changes in chemical constituents and some physical properties such as swelling and water absorption of hornbeam (Carpinus betulus L) and uludag fir (Abies bornmulleriana Mattf.) wood were investigated after heat treatment at three different temperatures (170 oC, 190 oC, and 210 oC) for three different durations (4, 8, and 12 hours) by using thermal gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectrometry. The results of TGA show that there was less weight loss in the main degradation region (300-500 oC) for the heat-treated samples as compared to untreated (control) samples. In addition, there was greater weight loss of hornbeam wood than of uludag fir wood in a similar degradation region. This difference could be due to the chemical constituents of softwoods and hardwoods. The results of FTIR spectrometry show that the chemical constituents of the hornbeam wood samples were more affected by heat treatment. All heat-treated samples exhibited lower water absorption and swelling compared to control samples. It was found that the relative decrease in swelling and water absorption for uludag fir was higher than for hornbeam. The maximum decrease in water absorption and swelling was found for both species that were heat-treated at 210 oC for 12 hours.

Changes in the chemical structure of thermally treated wood

Changes in the chemical structure of hornbeam and uludag fir woods during thermal treatment were investigated at three temperatures (170, 190, and 210 oC) and three durations (4, 8, and 12 hours). After thermal treatment, the extents of degradation in the chemical structure of the samples were determined, and the effects on the chemical composition of hornbeam wood and uludag fir wood were investigated. The data obtained were analyzed using variance analysis, and Tukey’s test was used to determine the changes in the chemical structure of uludag fir and hornbeam woods. The results showed that heating wood permanently changes several of its chemical structures and that the changes are mainly caused by thermal degradation of wood polymers. It was found that decreasing of the cellulose and holocelluloses ratio had a favorable effect on the interaction of the wood with moisture. According to the obtained results, hornbeam wood is affected more than uludag fir wood. For each wood, the maximum decreases of holocellulose and α-cellulose were found at 210oC for 12 hours, and the maximum increase of lignin occurred at the same treatment combination.

The Effect of Heat Treatment on Some Mechanical Properties and Color Changes of Uludag Fir Wood

In this study, the effects of heat treatment on color, mass loss, compression strength, and hardness of Uludag fir (Abies bornmulleriana Mattf.) were investigated. Wood specimens conditioned at a relative humidity of 65% and a temperature of 20°C were subjected to heat treatment at 170, 190, and 210°C for 4, 8, and 12 h. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. Color changes were determined according to DIN5033. The results showed that compression strength and hardness of Uludag fir wood decreased to varying extents in relation to intensity of treatment, whereas mass loss increased. We determined that treatment temperature had a more significant effect on color changes than did treatment time. The color of the wood became darker at the higher treatment temperatures.

Impact of impregnation chemical on the bending strength of solid and laminated wood materials

The aim of this study was to investigate the effect of impregnation chemical on the bending strength of the solid and laminated wood materials. For this aim, Oriental beech, European oak, Scotch pine, Oriental spruce and Uludag fir woods impregnated with Imersol Aqua according to ASTM D 1413-99 and producers’ definition. Laminated wood samples were produced from the impregnated wood materials according to TS EN 386 in the five ply form (4 mm each) from beech, oak, pine, fir and spruce wood by using Desmodur-VTKA adhesive. The bending strength values were measured according to TS EN 408. Consequently, the bending strength of impregnated + laminated (I + L W) softwoods, pine, spruce and fir increased, respectively by 10.06%, 1.83% and 5.78% whereas the bending strength of impregnated + laminated hardwoods, beech and oak decreased, respectively by 4.78% and 9.15% with respect to laminated control samples (L W). Considering the interaction of wood type and process, the bending strength was obtained from laminated Oriental beech, whereas the lowest was found for impregnated Uludag fir. In consequence, in the massive construction and furniture elements that the bending strength after the impregnation and lamination (I + L W) is of great concern, beech and pine materials could be recommended.

Impact of impregnation chemical on surface glossiness of synthetic, acrylic, polyurethane, and water‐based varnishes

AbstractThis study was performed to determine the effects of impregnation chemical on surface glossiness of some varnishes. For this purpose, the test samples prepared from Oriental beech, European oak, Scotch pine, Oriental spruce, and Uludag fir woods according to ASTM D 358 were impregnated with Imersol‐Aqua according to ASTM D 1413 and producer's definition by short‐term (S), medium‐term (M), and long‐term (L) of dipping methods and coated by synthetic (Sv), acrylic (Ac), water‐based (Wb), and polyurethane (Pu) varnishes according to ASTM D 3023. After the varnishing process, the surface glossiness parallel to fibers was determined according to TS 4318. Consequently, among the nonimpregnated wood samples, surface glossiness parallel to fibers was found to be the highest in Oriental spruce and the lowest in European oak. As for the period of dipping, the highest surface glossiness was obtained in medium‐term dipping and the lowest in long‐term dipping. As for the varnish types, the surface glossiness was found to be the highest in polyurathane varnish and the lowest in water‐based varnish. Considering the interaction of wood type, period of impregnation, and type of varnish, surface glossiness was the highest in Uludag fir, long‐term dipping, and polyurathane varnish (103.9 gloss) and the lowest in Oriental beech, long‐term dipping, and water‐based varnish (67.78 gloss). In consequence, in the massive constructions and furniture elements the surface glossiness parallel to fibers after the impregnation with Imersol‐Aqua is of great concern, long‐term impregnation of Uludag fir materials could be recommended. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Impacts of impregnation with Timbercare Aqua on the red and yellow color tone of some woods and varnishes

AbstractThis study has been performed for determining the effects of impregnation with Timbercare Aqua (Tc) on the red and yellow color tone of some woods and varnishes. For this purpose, the test samples prepared from Oriental beech, European oak, Scotch pine, Oriental spruce, and Uludag fir woods, which met the requirements of ASTM D 358, was impregnated with Tc according to ASTM D 1413 and producer's definition. After impregnation, wood surfaces have been coated by Sayerlack parquet varnish (Sp), Sayerlack interior varnish (Si), and Sayerlack exterior varnish (Se) varnishes in accordance with the ASTM D 3023 standards. According to ASTM D 2244, the red and yellow color tone of samples after varnishing process was determined. As a result, the value of red color tone was the highest in Oriental beech (15.21) and the lowest in Uludag fir (5.38). For the wood material, impregnation material, and varnish interaction, the red color tone value was the highest in Oriental beech + Tc + Sp (18.43) and the lowest in Uludag fir + Tc + Si (3.92). The value of the yellow color tone was the highest in pine (34.45) and the lowest in Oriental beech (26.50). For the wood material, impregnation material, and varnish interaction, the yellow color tone value was the highest in Oriental spruce + Tc + Sp (42.12) and the lowest in Oriental beech + Tc + Si (21.47). This effect may be due to the impacts of impregnation chemical on wood extractives and color pigments in varnish. Accordingly, it should be taken into care for applications where the red and yellow color tone value is important. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Impacts of coating with various varnishes after impregnation with boron compounds on the combustion properties of Uludag fir

This study was performed to determine the effects of varnishing after impregnation with boron compounds on combustion properties of Uludag Fir. For this purpose, the test samples prepared from Uludag fir (Abies Bornmülleriana Mattf.) wood were impregnated according to ASTM D 1413-99 with boric acid (Ba) and borax (Bx) by vacuum technique. After impregnation, surfaces were coated by cellulosic (Cv), synthetic (Sn), polyurethane (Pu), waterborne (Wb), acrylic (Ac), and acid hardening (Ah) varnishes in accordance to ASTM D 3023. Combustion properties of samples after varnishing process were determined according to ASTM E 160-50. According to material and process type, combustion temperature was highest in without flame source combustion (WFSC), Bx, and Wb but the lowest in flame source combustion (FSC), Ba, and Pu. For the combination of combustion type, impregnation material and varnish type, combustion temperature was the highest in WFSC + Ba + Wb combination but the lowest in WFSC + Ba + Cv combination. Consequently, the tested varnishes showed an increasing impact but boron compounds (Ba and Bx) showed a decreasing impact on combustion properties of Uludag fir wood. In consequence, for usage areas having a high risk of fire, impregnation of wood material with boron compounds before varnishing will decrease combustion temperature and provide security. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Crystalline structure of heat-treated Scots pine [Pinus sylvestris L.] and Uludağ fir [Abies nordmanniana (Stev.) subsp. bornmuelleriana (Mattf.)] wood

The aim of this study was to determine changes in crystallinity and crystalline unit cell type of heat-treated Scots pine (Pinus sylvestris L.) and Uludag fir (Abies nordmanniana stev. subsp. bornmuelleriana Mattf.) wood samples by means of FT-IR spectroscopic method. Heat treatment was applied on the test samples in an oven at three different temperatures (120, 150, and 180°C) and for two different periods of time (6 and 10 h) under atmospheric pressure. It was designated that crystallinity of both Scots pine and Uludag fir wood samples increased during heat treatment depending on the duration. However, monoclinic structure in crystalline unit cells of Scots pine and Uludag fir wood samples converted to triclinic structure when heat treated. It was estimated that monoclinic structure was dominant in the crystalline unit cell. It was established that the crystalline structure of Scots pine wood samples was more affected by heat treatment than that of Uludag fir wood samples.